There were countless horrors in the wars which led to the break-up of Yugoslavia in the 1990s. A Serbian army general has now surrendered to the authorities and will go to the United Nations tribunal in The Hague to answer war crimes charges dating back to 1999. But what happens once camp guards have served their sentences?

Dragan Kolundžija, Kole to his friends, is sitting at the bar of the Hotel Prijedor when we enter.

He smiles awkwardly and gets down off the stool to shake hands.

He looks younger than his 46 years.

If you saw him in the street, you could mistake him for a football coach.

Not a reserve policeman.

Not a concentration camp guard.

He has not agreed to an interview yet. He has turned down the approaches of other journalists.

It takes Lola 10 minutes to persuade him to speak.

Lola, my fixer, who fought for a while in the same Bosnian Serb army as Kole and tells dirty jokes all day long, has a heart of gold and is not afraid of anything.

Meanwhile, I watch the women cleaning the glass panels which dot the lobby of this hotel.

Then we go upstairs to a big empty room with a gas heater.

The hotel staff seem afraid of us, or of Kole, I cannot decide which.

'Tortured to death'

Kole was a guard at Keraterm in 1992, one of three concentration camps in north-west Bosnia, where nearly 1,700 Bosnian Muslims were tortured to death in three months in the summer of 1992.

Thousands of others still bear the scars.

He pleaded guilty to one count of persecution as a crime against humanity. And got three years in jail from the Hague War Crimes Tribunal.

And was one of the first to be released.

Five of his fellow guards are still serving sentences.

‘There were 30 in total’, he says.

Sitting with him, it is easy to remember that the Serbs too are victims of the Bosnian war.

That the jailers too, suffer.

His hands shake badly. And his lips.

He tries to hold his hands still on the pure white tablecloth.

We make small talk for a while, but I cannot pretend we have come to talk about the river, which flows lazily by, beneath the windows.

I try to be gentle.

I am a storyteller, not a prosecutor.

What ways were open to you to show kindness to the prisoners?

He breaks down immediately.

Unusual friendship

After a while, he says he has a friend.

A Muslim, who was an inmate at the camp, when he was a guard.

Would we like to meet him?

Ten minutes later Suad, known as Duda, is there.

He too is trembling.

The Serb and the Muslim, the guard and his prisoner are sitting side-by-side, broken faced, broken eyed, drinking stupid soft drinks as though there was no war, no cruelty, no injustice in this world.

‘We guards were much closer to robots than to human beings... we were all doing things which were not connected to our true selves...’, says Kole.

‘There was chaos in the compound, and chaos outside in the town. And men with guns.’

They explain to me, in fits and starts, what a concentration camp means.

What the concentration of men means.

It is where men are concentrated to death.

Four rooms with 400-500 men in each, 120 metres square.

In the summer heat. With no space to lie down.

Civilians, from 15 to 90-years-old.

Rounded up at the start of the war on the orders of the high command, zealously carried out by local henchmen.

Muslims had been officially declared vermin.

So they had to be concentrated.

Every night Serb soldiers, back from the front, came to the camp.

They wanted revenge for lost comrades.

They asked the guards for the keys to the rooms.

And committed acts of unspeakable barbarity. Of sexual humiliation and horror.

Of all the guards, only Kole refused to hand over the key, says Duda.

That was the only shift when there were no beatings or killings.

Except for just one night.

'Dark black night'

‘It was dark, the soldiers somehow got into the room and Kole was shouting, stop shooting, stop shooting!’ Duda says. ‘By morning there were 200 bodies.’

Kole is hunched up at the table, staring at the back of his hands, as though he does not know what they are. After a while he says, ‘that was a dark black night’. At the Hague, Duda testified in his defence. Partly thanks to that, Kole is out already. The judges believed he did what he could, to alleviate the suffering. Now the two men are friends again. Like they were at primary school. After the interview, I try to find the toilet but my brain is fogged up. I walk headfirst into a plate glass door. The women cleaned it too well. It quivers but does not break. I walk with my hands in front of me now, like a blind man.

But there are those who still believe in a final solution to the 'Muslim problem'

This hotel, this country is a labyrinth of invisible glass.

On the way out of Prijedor, we pass Keraterm, the ex-camp. Once a factory for bathroom tiles.

It is a low, meaningless building beside another factory, which boasts a chimney at least, for making bricks.

25,000 Muslims are back in Prijedor. Out of the 45,000 who once lived here.

Some stare at Kole in the street. Some shake his hand.

Nearly everyone was changed by the war.

But there are those who still believe in a final solution to the ‘Muslim problem’.

That one race, or ethnic group, is better than another.

But if Kole and Duda can live together anyone can.

Nick Thorpe’s report in the series ‘From Our Own Correspondent’ was broadcast on 29 January 2005 on BBC Radio 4.